/* Flot plugin that adds some extra symbols for plotting points.

Copyright (c) 2007-2014 IOLA and Ole Laursen.
Licensed under the MIT license.

The symbols are accessed as strings through the standard symbol options:

    series: {
        points: {
            symbol: "square" // or "diamond", "triangle", "cross", "plus", "ellipse", "rectangle"
        }
    }

*/

(function ($) {
  // we normalize the area of each symbol so it is approximately the
  // same as a circle of the given radius

  var square = function (ctx, x, y, radius, shadow) {
      // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
      var size = radius * Math.sqrt(Math.PI) / 2;
      ctx.rect(x - size, y - size, size + size, size + size);
    },
    rectangle = function (ctx, x, y, radius, shadow) {
      // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
      var size = radius * Math.sqrt(Math.PI) / 2;
      ctx.rect(x - size, y - size, size + size, size + size);
    },
    diamond = function (ctx, x, y, radius, shadow) {
      // pi * r^2 = 2s^2  =>  s = r * sqrt(pi/2)
      var size = radius * Math.sqrt(Math.PI / 2);
      ctx.moveTo(x - size, y);
      ctx.lineTo(x, y - size);
      ctx.lineTo(x + size, y);
      ctx.lineTo(x, y + size);
      ctx.lineTo(x - size, y);
      ctx.lineTo(x, y - size);
    },
    triangle = function (ctx, x, y, radius, shadow) {
      // pi * r^2 = 1/2 * s^2 * sin (pi / 3)  =>  s = r * sqrt(2 * pi / sin(pi / 3))
      var size = radius * Math.sqrt(2 * Math.PI / Math.sin(Math.PI / 3));
      var height = size * Math.sin(Math.PI / 3);
      ctx.moveTo(x - size / 2, y + height / 2);
      ctx.lineTo(x + size / 2, y + height / 2);
      if (!shadow) {
        ctx.lineTo(x, y - height / 2);
        ctx.lineTo(x - size / 2, y + height / 2);
        ctx.lineTo(x + size / 2, y + height / 2);
      }
    },
    cross = function (ctx, x, y, radius, shadow) {
      // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
      var size = radius * Math.sqrt(Math.PI) / 2;
      ctx.moveTo(x - size, y - size);
      ctx.lineTo(x + size, y + size);
      ctx.moveTo(x - size, y + size);
      ctx.lineTo(x + size, y - size);
    },
    ellipse = function (ctx, x, y, radius, shadow, fill) {
      if (!shadow) {
        ctx.moveTo(x + radius, y);
        ctx.arc(x, y, radius, 0, Math.PI * 2, false);
      }
    },
    plus = function (ctx, x, y, radius, shadow) {
      var size = radius * Math.sqrt(Math.PI / 2);
      ctx.moveTo(x - size, y);
      ctx.lineTo(x + size, y);
      ctx.moveTo(x, y + size);
      ctx.lineTo(x, y - size);
    },
    handlers = {
      square: square,
      rectangle: rectangle,
      diamond: diamond,
      triangle: triangle,
      cross: cross,
      ellipse: ellipse,
      plus: plus
    };

  square.fill = true;
  rectangle.fill = true;
  diamond.fill = true;
  triangle.fill = true;
  ellipse.fill = true;

  function init(plot) {
    plot.drawSymbol = handlers;
  }

  $.plot.plugins.push({
    init: init,
    name: 'symbols',
    version: '1.0'
  });
})(jQuery);
